The city has attacked this problem on and under the ground with a hotline to report sinkholes, metal plates covering them and technology to search for the leaks in the pipes that erode the soil, creating them.

Though recent media attention has focused on Harrisburg, state officials outside its borders report sinkholes as a common occurrence.

HARRISBURG’S TRIAGE APPROACH

As Harrisburg monitors and repairs the two large sinkholes on North Fourth Street and pipes underneath, no others have sprung up.

“Right now, there are no extreme situations in the city,” said Robert Philbin, Mayor Linda Thompson’s spokesman, said Thursday.

“We have sinkholes, but none that we can observably say are going to collapse.”

No new sinkholes have been found since the North Fourth Street collapse — the worst that anyone in the Public Works Department has seen in the state’s Capital, he said.

For now, Harrisburg officials are using a three-prong approach to stay on top of the situation.

The first step is increased public involvement. On Tuesday, the city set up a hotline — 717-225-6524 — for residents to call, when they notice the beginnings of a sinkhole.

A slight, downward slope that is usually square shaped is the calling card of the beginning stages in a road, Philbin said.

“It’s an early indication that something’s wrong underneath,” he said. “It might not be a sinkhole, but it’s something the city looks for.”

So far, the permanent hotline hasn’t received any reports of sinkholes, Philbin said.

Secondly, the public works crews keep their eyes peeled for sinkholes.

If it’s a minor sinkhole, workers can install a steel plate overtop as long as the street’s sub-structure is strong enough to support it.

But when the asphalt is crumbling to the touch, Philbin said it could be the makings of a bigger problem like the monsters on North Fourth Street.

In these cases, crews open the hole, dig down into it, repair the leaky pipes likely causing the problem, and fill it back in, which is what crews are doing on North Fourth Street, he said.

Thirdly, Philbin said the city now is using a flexible, snake camera that weaves through underground water pipes, searching for sinkhole-creating leaks, which haven’t yet been discovered.

The city’s Public Works Department wants to expand these efforts, and is looking for funding to bring in sonar technology for early detection below the surface.

NOT JUST A HARRISBURG PROBLEM

Sinkholes are not just a Harrisburg problem.

Greg Penny, community relation’s coordinator for the Pennsylvania Department of Transportation, said PennDOT deals with its fair share of them.

It’s been such a problem that a bar on the same block has been aptly named The Sinkhole Saloon & Grille.

“We’re looking at a more permanent solution, but right now, funding is a challenge,” Penny said.

A permanent fix can cost upward of $1 million in some cases, he said.

PennDOT does not have a budget specifically for sinkholes, Penny said, but he estimates the smaller ones usually cost about $10,000 to $20,000 to fix.

PennDOT sunk about $200,000 during the past couple of years into the problematic one near The Sinkhole Saloon.

While leaking water and sewer pipes beneath the streets is a major cause of Harrisburg’s sinkholes, PennDOT encounters sinkholes created when water erodes away the soil beneath the pavement.

The sinkholes also can occur because runoff from housing developments soaks up under the road, eroding away the soil beneath, he said.

Pennsylvania is also subject to sinkholes from underground limestone that erodes and creates holes in the earth, which can expand to nearby roads, Penny said.

Because sinkholes are potential hazards, especially on roads, Penny said PennDOT tries to respond as quickly as possible to contain them. Residents can call 1-800-FIX-ROAD to report sinkholes directly to PennDOT, or their local police and municipalities to report the problem, Penny said.

“We deal with them on a fairly regular basis,” Penny said. “We explore it and we excavate, and try to find the throat and plug it.”

MAINTENANCE IS KEY

In other nearby areas, Hershey-based Pennsylvania American Water has more than 10,000 miles of water lines coursing throughout the state, including Camp Hill whose lines dated to 1916.

Pennsylvania American Water regularly maintains its lines, which crack when the pipes freeze and thaw, contract and expand.

The company tries to coincide its repairs with other infrastructure work taking place and before road repaving projects are planned so the road doesn't have to be torn up repeatedly, said spokesman Terry Maenza.

"Infrastructure is critical to our communities and the problem is, it's underground, out of sight out of mind. …," he said. "Because a pipe is old, it's more susceptible (to damage), so you can't just leave it there (if major damage occurs).

“If you neglect it and you don't reinvest, these are the problems you are going to see — breaks and outages for your customers."

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